Solid-state relay dedicated recirculation path systems and methods

ABSTRACT

Disclosed is a battery system comprising a solid-state relay assembly comprising a device-side driver circuitry having a device-side switching device, a battery-side driver circuitry having a battery-side switching device, a first recirculation driver circuitry, a first recirculation switching device, a second recirculation switching device, and a second recirculation driver circuitry.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/752,792 entitled “Solid-State Relay Dedicated Recirculation PathSystems and Method,” filed Oct. 30, 2018.

FIELD

The present disclosure generally relates to battery systems and, moreparticularly, to solid-state relays that may be coupled to orimplemented in a battery system.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present disclosure,which are described below. This discussion is believed to be helpful inproviding the reader with background information to facilitate a betterunderstanding of the various aspects of the present disclosure.Accordingly, it should be understood that these statements are to beread in this light, and not as admissions of prior art.

An automotive vehicle that uses one or more battery systems forproviding all or a portion of the motive power for the vehicle can bereferred to as an xEV, where the term “xEV” is defined herein to includeall of the following vehicles, or any variations or combinationsthereof, that use electric power for all or a portion of their vehicularmotive force. For example, xEVs include electric vehicles (EVs) thatutilize electric power for all motive force. As will be appreciated bythose skilled in the art, hybrid electric vehicles (HEVs), alsoconsidered xEVs, combine an internal combustion engine propulsion systemand a battery-powered electric propulsion system, such as but notlimited to 48 Volt (V) or 130V systems. The term HEV may include anyvariation of a hybrid electric vehicle. For example, full hybrid systems(FHEVs) may provide motive and other electrical power to the vehicleusing one or more electric motors, using only an internal combustionengine, or using both. In contrast, mild hybrid systems (MHEVs) maydisable the internal combustion engine when the vehicle is idling andutilize a battery system to continue powering the air conditioning unit,radio, or other electronics, as well as to restart the engine whenpropulsion is desired. The mild hybrid system may also apply some levelof power assist, during acceleration for example, to supplement theinternal combustion engine.

Further, a micro-hybrid electric vehicle (mHEV) also may use a“Stop-Start” system similar to the mild hybrids, but the micro-hybridsystems of a mHEV may or may not supply power assist to the internalcombustion engine and operates at a voltage below 60V. For the purposesof the present discussion, it should be noted that mHEVs may nottechnically use electric power provided directly to the crankshaft ortransmission for any portion of the motive force of the vehicle, but anmHEV may still be considered as an xEV since it does use electric powerto supplement a vehicle's power needs when the vehicle is idling withinternal combustion engine disabled.

In addition, a plug-in electric vehicle (PEV) is any vehicle that can becharged from an external source of electricity, such as wall sockets,and the energy stored in the rechargeable battery packs drives orcontributes to drive the wheels. PEVs are a subcategory of EVs thatinclude all-electric or battery electric vehicles (BEVs), plug-in hybridelectric vehicles (PHEVs), and electric vehicle conversions of hybridelectric vehicles and conventional internal combustion engine vehicles.

xEVs as described above may provide a number of advantages as comparedto more traditional gas-powered vehicles using only internal combustionengines and traditional electrical systems, which are typically 12Vsystems powered by a lead-acid battery. In fact, xEVs may produce fewerundesirable emission products and may exhibit greater fuel efficiency ascompared to traditional internal combustion vehicles. For example, somexEVs may utilize regenerative braking to generate and store electricalenergy as the xEV decelerates or coasts. More specifically, as the xEVreduces in speed, a regenerative braking system may convert mechanicalenergy into electrical energy, which may then be stored and/or used topower to the xEV.

As technology continues to evolve, there is a need to provide improvedpower sources, particularly battery modules, for such vehicles. Further,there is a need to provide improved connections between the powersources and vehicle. As a non-limiting example, there is a need toensure power irregularities do not damage electronic components.

SUMMARY

Certain embodiments commensurate in scope with the disclosed subjectmatter are summarized below. These embodiments are not intended to limitthe scope of the disclosure, but rather these embodiments are intendedonly to provide a brief summary of certain disclosed embodiments.Indeed, the present disclosure may encompass a variety of forms that maybe similar to or different from the embodiments set forth below.

Disclosed is a solid-state relay system which may address certaindeficiencies outlined above. Generally, a solid-state relay may becontrolled to selectively operate in a connected (e.g., closed) state,which enables current flow therethrough, and a disconnected (e.g., open)state, which blocks current flow therethrough. Thus, in someembodiments, a solid-state-relay assembly may be electrically coupledbetween a battery and one or more electrical devices (e.g., anelectrical system) to facilitate controlling current flow therebetweenand, thus, charging and/or discharging of the battery.

The disclosed solid state relay system may advantageously allow for arecirculation path. The recirculation path may advantageously routeexcess energy away from electronics in an irregular event. For example,the disclosed recirculation path may advantageously protect componentsin a reverse polarity event.

Disclosed is a battery system comprising: a battery; a solid-state relaysystem; and a control system; wherein the solid-state relay systemcomprises a first battery-side switching device, first device-sideswitching device, and a recirculation path. Further disclosed is abattery system wherein the solid-state relay system further comprises asecond battery-side switching device and third battery-side switchingdevice, a second device-side switching device and third device-sideswitching device. Further disclosed is a battery system wherein therecirculation path comprises a first recirculation switching device.Further disclosed is a battery system wherein the recirculation pathfurther comprises a second recirculation switching device. Furtherdisclosed is a battery system wherein the first recirculation switchingdevice comprises a metal-oxide-semiconductor field-effect transistor.Further disclosed is a battery system wherein both the firstrecirculation switching device and the second recirculation switchingdevice each comprise a metal-oxide-semiconductor field-effecttransistor. Further disclosed is a battery system wherein the firstrecirculation switching device connects to a first recirculation drivercircuitry and the second recirculation device connects to a secondrecirculation driver circuitry. Further disclosed is a battery systemwherein each of the first battery-side switching device, secondbattery-side switching device, third battery-side switching device,first device-side switching device, second device-side switching deviceand third device-side switching device each comprise a metal-oxidesemiconductor field-effect transistor.

Disclosed is a solid-state relay assembly for a battery systemcomprising: a device-side driver circuitry having a device-sideswitching device; a battery-side driver circuitry having a battery-sideswitching device; a first recirculation driver circuitry; a firstrecirculation switching device; a second recirculation switching device;and a second recirculation driver circuitry. Further disclosed is asolid-state relay assembly wherein the first recirculation switchingdevice, second recirculation switching device, or both the firstrecirculation switching device and second recirculation switching devicecomprise a metal-oxide semiconductor field-effect transistor. Furtherdisclosed is a solid-state relay assembly wherein the device-sideswitching device comprises a first, second, and third device-sideswitching device. Further disclosed is a solid-state relay assemblywherein the battery-side switching device comprises a first, second, andthird battery-side switching device. Further disclosed is a solid-staterelay assembly wherein the device-side switching device is a metal-oxidesemiconductor field-effect transistor. Further disclosed is asolid-state relay assembly wherein the battery-side switching device isa metal-oxide semiconductor field-effect transistor.

These and other features and advantages of devices, systems, and methodsaccording to this invention are described in, or are apparent from, thefollowing detailed descriptions of various examples of embodiments.

BRIEF DESCRIPTION OF DRAWINGS

Various examples of embodiments of the systems, devices, and methodsaccording to this invention will be described in detail, with referenceto the following figures, wherein:

FIG. 1 is a perspective view of a vehicle, in accordance with variousembodiments;

FIG. 2 is a schematic view of a battery system in the vehicle of FIG. 1,in accordance with various embodiments;

FIG. 3 is a detail view of a battery system according to variousembodiments;

FIG. 4 is a view of a solid state relay assembly for use with a batterysystem, according to various embodiments;

FIG. 5 is a workflow for operation of a solid state relay assembly foruse with a battery system, according to various embodiments;

FIG. 6 is a second workflow for operation of a solid state relayassembly for use with a battery system, according to variousembodiments; and

FIG. 7 is a detailed view of a solid state relay assembly for use with abattery system, according to various embodiments.

It should be understood that the drawings are not necessarily to scale.In certain instances, details that are not necessary to theunderstanding of the invention or render other details difficult toperceive may have been omitted. It should be understood, of course, thatthe invention is not necessarily limited to the particular embodimentsillustrated herein.

DETAILED DESCRIPTION

One or more specific embodiments of the present techniques will bedescribed below. In an effort to provide a concise description of theseembodiments, not all features of an actual implementation are describedin the specification. It should be appreciated that in the developmentof any such actual implementation, as in any engineering or designproject, numerous implementation-specific decisions must be made toachieve the developers' specific goals, such as compliance withsystem-related and business-related constraints, which may vary from oneimplementation to another. Moreover, it should be appreciated that sucha development effort might be complex and time consuming, but wouldnevertheless be a routine undertaking of design, fabrication, andmanufacture for those of ordinary skill having the benefit of thisdisclosure.

To help illustrate, FIG. 1 is a perspective view of an embodiment of avehicle 10, which may utilize a regenerative braking system. Althoughthe following discussion is presented in relation to vehicles withregenerative braking systems, the techniques described herein areadaptable to other vehicles that capture/store electrical energy with abattery, which may include electric-powered and gas-powered vehicles.

As discussed above, it would be desirable for a battery system 12 to belargely compatible with traditional vehicle designs. Accordingly, thebattery system 12 may be placed in a location in the vehicle 10 thatwould have housed a traditional battery system. For example, asillustrated, the vehicle 10 may include the battery system 12 positionedsimilarly to a lead-acid battery of a typical combustion-engine vehicle(e.g., under the hood of the vehicle 10). Furthermore, as will bedescribed in more detail below, the battery system 12 may be positionedto facilitate managing temperature of the battery system 12. Forexample, in some embodiments, positioning a battery system 12 under thehood of the vehicle 10 may enable an air duct to channel airflow overthe battery system 12 and cool the battery system 12.

A more detailed view of the battery system 12 is described in FIG. 2. Asdepicted, the battery system 12 includes an energy storage component 14coupled to an ignition system 16, an alternator 18, a vehicle console20, and optionally to an electric motor 22. Generally, the energystorage component 14 may capture/store electrical energy generated inthe vehicle 10 and output electrical energy to power electrical devicesin the vehicle 10.

In other words, the battery system 12 may supply power to components ofthe vehicle's electrical system, which may include radiator coolingfans, climate control systems, electric power steering systems, activesuspension systems, auto park systems, electric oil pumps, electricsuper/turbochargers, electric water pumps, heated windscreen/defrosters,window lift motors, vanity lights, tire pressure monitoring systems,sunroof motor controls, power seats, alarm systems, infotainmentsystems, navigation features, lane departure warning systems, electricparking brakes, external lights, or any combination thereof.Illustratively, in the depicted embodiment, the energy storage component14 supplies power to the vehicle console 20 and the ignition system 16,which may be used to start (e.g., crank) the internal combustion engine24.

Additionally, the energy storage component 14 may capture electricalenergy generated by the alternator 18 and/or the electric motor 22. Insome embodiments, the alternator 18 may generate electrical energy whilethe internal combustion engine 24 is running. More specifically, thealternator 18 may convert the mechanical energy produced by the rotationof the internal combustion engine 24 into electrical energy.Additionally or alternatively, when the vehicle 10 includes an electricmotor 22, the electric motor 22 may generate electrical energy byconverting mechanical energy produced by the movement of the vehicle 10(e.g., rotation of the wheels) into electrical energy. Thus, in someembodiments, the energy storage component 14 may capture electricalenergy generated by the alternator 18 and/or the electric motor 22during regenerative braking. As such, the alternator 18 and/or theelectric motor 22 are generally referred to herein as a regenerativebraking system.

To facilitate capturing and supplying electric energy, the energystorage component 18 may be electrically coupled to the vehicle'selectric system via a bus 26. For example, the bus 26 may enable theenergy storage component 14 to receive electrical energy generated bythe alternator 18 and/or the electric motor 24. Additionally, the bus 26may enable the energy storage component 14 to output electrical energyto the ignition system 16 and/or the vehicle console 20. Accordingly,when a 12 volt battery system is used, the bus 26 may carry electricalpower typically between 8-18 volts.

Additionally, as depicted, the energy storage component 14 may includemultiple battery modules. For example, in the depicted embodiment, theenergy storage component 13 includes a lithium ion (e.g., a first)battery module 28 and a lead-acid (e.g., a second) battery module 30,which each includes one or more battery cells. In other embodiments, theenergy storage component 14 may include any number of battery modules.Additionally, although the lithium ion battery module 28 and lead-acidbattery module 30 are depicted adjacent to one another, they may bepositioned in different areas around the vehicle. For example, thelead-acid battery module 30 may be positioned in or about the interiorof the vehicle 10 while the lithium ion battery module 28 may bepositioned under the hood of the vehicle 10.

In some embodiments, the energy storage component 14 may includemultiple battery modules to utilize multiple different batterychemistries. For example, when the lithium ion battery module 28 isused, performance of the battery system 12 may be improved since thelithium ion battery chemistry generally has a higher coulombicefficiency and/or a higher power charge acceptance rate (e.g., highermaximum charge current or charge voltage) than the lead-acid batterychemistry. As such, the capture, storage, and/or distribution efficiencyof the battery system 12 may be improved.

To facilitate controlling the capturing and storing of electricalenergy, the battery system 12 may additionally include a control module32. More specifically, the control module 32 may control operations ofcomponents in the battery system 12, such as relays (e.g., switches)within energy storage component 14, the alternator 18, and/or theelectric motor 22. For example, the control module 32 may regulateamount of electrical energy captured/supplied by each battery module 28or 30 (e.g., to de-rate and re-rate the battery system 12), perform loadbalancing between the battery modules 28 and 30, determine a state ofcharge of each battery module 28 or 30, determine temperature of eachbattery module 28 or 30, control voltage output by the alternator 18and/or the electric motor 22, and the like.

Accordingly, the control unit 32 may include one or more processor 34and one or more memory 36. More specifically, the one or more processor34 may include one or more application specific integrated circuits(ASICs), one or more field programmable gate arrays (FPGAs), one or moregeneral purpose processors, or any combination thereof. Additionally,the one or more memory 36 may include volatile memory, such as randomaccess memory (RAM), and/or non-volatile memory, such as read-onlymemory (ROM), optical drives, hard disc drives, or solid-state drives.In some embodiments, the control unit 32 may include portions of avehicle control unit (VCU) and/or a separate battery control module.

To help further illustrate, an example of a battery system 110 includinga battery 112, a solid-state relay assembly 114, one or more electricaldevices 116, and a control system 118 is shown in FIG. 3. As in thedepicted example, a battery 112 may include battery terminals 124 andone or more battery cells 122. In some embodiments, the battery cells122 may be electrically coupled (e.g., in series and/or parallel)between the battery terminals 124 to enable the battery 112 to provide atarget storage capacity, exhibit a target internal resistance, and/oroperate in a target voltage domain (e.g., range). For example, thebattery cells 122 may be electrically coupled between the batteryterminals 124 to enable the battery 112 to operate in a 1V voltagedomain, a 12V voltage domain, a 48V voltage domain, a 100V voltagedomain, a 1000V voltage domain, or the like. In other words, the battery112 may be a 1V battery, a 12V battery, a 48V battery, a 100V battery, a1000V battery, or the like.

Additionally, in some embodiments, the battery 112 may include a batterypack or a battery module. In other words, in such embodiments, thebattery 112 may include a housing that encloses the battery cells 122and/or on which the battery terminals 124 are implemented. In any case,a battery cell 122 may generally operate to store received electricalpower as electrical energy and/or to output electrical power usingstored electrical energy.

Furthermore, as in the depicted example, the electrical devices 116 mayinclude one or more electrical loads 130 that operate using receivedelectrical power. In some embodiments, the electrical devices 116 mayadditionally or alternatively include one or more electrical generators132, which operate to output electrical power. For example, anelectrical generator 132 may include an alternator that outputselectrical power using mechanical energy received from an internalcombustion engine or another mechanical energy source.

Moreover, as in the depicted example, the solid-state relay assembly 114may be electrically coupled between the battery cells 122 and theelectrical devices 116. In some embodiments, the control system 118 maygenerally control operation of the battery system 110 and, thus, may becommunicatively coupled to the solid-state relay assembly 114. In otherwords, the control system 118 may output control signals (e.g.,commands) instructing the solid-state relay assembly 114 to switch froma first (e.g., connected) state to a second (e.g., disconnected ordifferent connected) state or vice versa. Additionally or alternatively,the control system 118 may output control signals instructing thesolid-state relay assembly 114 to maintain the first state and/or thesecond state.

In some embodiments, the control system 118 may be implemented at leastin part in a battery management unit (BMU) and/or a vehicle control unit(VCU). In some embodiments, the solid-state relay assembly may beintegrated within the BMU or separate therefrom. Additionally, in someembodiments, the control system 118 may control operation of the batterysystem 110 based at least in part on operational parameters (e.g.,sensor data) measured by one or more sensors 120. For example, whenoperational parameters (e.g., voltage and/or current) of the batterysystem 110 are indicative of a short-circuit condition being present,the control system 118 may instruct (e.g., via a control signal) thesolid-state relay assembly 114 to switch from a connected state to thedisconnected state, thereby electrically disconnecting the battery 112from the electrical devices 116.

In some embodiments, the solid-state relay assembly 114 may beimplemented external to the battery 112, for example, such that thesolid-state relay assembly 14 is external from the housing of thebattery 112. Thus, in such embodiments, the solid-state relay assembly114 may be electrically coupled to a (e.g., positive) battery terminal124 of the battery 112. For example, the solid-state relay assembly 114may be electrically coupled to the battery 112 via one or morebattery-side electrical busses 128. Alternatively, the solid-state relayassembly 114 may be directly coupled to a battery terminal 124 of thebattery 112, thereby obviating the battery-side electrical busses 128.

In other embodiments, the solid-state relay assembly 114 may beimplemented within the housing of the battery 112. In other words, insuch embodiments, the solid-state relay assembly 114 may be electricallycoupled between the battery cells 122 and the battery terminal 124 ofthe battery 112. In any case, as in the depicted example, thesolid-state relay assembly 114 may be electrically coupled to theelectrical devices 116 via one or more device-side electrical busses126.

Thus, as in the depicted example, the solid-state relay assembly 114 maybe electrically coupled between the battery cells 122 and the electricaldevices 116 to facilitate controlling flow of electrical powertherebetween. For example, in a connected state, the solid-state relayassembly 114 may enable electrical power to flow from a battery cell 122to an electrical load 130, thereby discharging the battery cell 122 topower the electrical load 130, and/or enable electrical power to flowfrom an electrical generator 132 to the battery cell 122, therebycharging the battery cell 122. On the other hand, in a disconnectedstate, the solid-state relay assembly 114 may block electrical powerfrom flowing between a battery cell 122 and the electrical devices 116,thereby blocking charging and/or discharging of the battery cell 122.

To facilitate controlling flow of electrical power, as in the depictedexample, the solid-state relay assembly 114 may include one or moreswitching devices 134. In some embodiments, the solid-state relayassembly 114 additionally include driver circuitry 136 coupled to aswitching device 134, for example, which facilitates controllingoperation (e.g., switching) of the switching device 134 based at leastin part on a control signal received from the control system 118. Thus,in such embodiments, the driver circuitry 136 may be coupled between thecontrol system 118 and the switching device 134.

In some embodiments, one or more of the switching devices 134 may beimplemented using semiconductor switching devices 134, for example, tofacilitate controlling flow (e.g., direction and/or presence) ofelectrical power between the battery 112 and the electrical devices 116.To help illustrate, an example of a solid-state relay assembly 114Aimplemented using semiconductor switching devices 134 is shown in FIG.4. As in depicted example, the solid-state relay assembly 114A mayinclude a battery-side terminal 138 and a device-side terminal 140.

Additionally, as in the depicted example, the solid-state relay assembly114A may include one or more battery-side switching devices 142electrically coupled to the battery-side terminal 138. Furthermore, asin the depicted example, the solid-state relay assembly 114A may includeone or more device-side switching devices 144 electrically coupled tothe device-side terminal 140. As described above, the switching devices134 in the solid-state relay assembly 114A may be implemented usingsemiconductor switching devices 134.

To help streamline discussion, the present disclosure describes examplesimplemented using metal-oxide-semiconductor field-effect transistors(MOSFETs) 146, which each include an intrinsic body diode 148. Forexample, a battery-side switching device 142 may include ametal-oxide-semiconductor field-effect transistor 146 implemented suchthat its drain is coupled to the battery-side terminal 138.Additionally, a device-side switching device 44 may include ametal-oxide-semiconductor field-effect transistor 146 implemented suchthat its drain is coupled to the device-side terminal 140. In otherwords, as in the depicted example, the battery-side switching device 142and the device-side switching device 144 may be electrically coupled ata first (e.g., common source) node 150. However, it should beappreciated that the depicted example is merely intended to beillustrative and not limiting. In particular, it should be appreciatedthat the techniques described in the present disclosure may implementedusing and/or adapted for use with other types of semiconductor switchingdevices 134.

In any case, to facilitate controlling operation of the solid-staterelay assembly 114A, control signals (e.g., output from the controlsystem 18) may be supplied to the semiconductor switching devices 134.For example, a battery-side control signal 152 may be supplied to acontrol input (e.g., gate) of a battery-side switching device 142 toselectively activate the battery-side switching device 142.Additionally, a device-side control signal 154 may be supplied to acontrol input (e.g., gate) of a device-side switching device 144 toselectively activate the device-side switching device 144.

In some embodiments, implementing a solid-state relay assembly 114 inthis manner may enable the solid-state relay assembly 114 to selectivelyprovide a disconnected (e.g., open) state as well as multiple connected(e.g., closed) states, which facilitate controlling (e.g., limiting)direction and/or presence of electrical power flowing between thebattery-side terminal 138 and the device-side terminal 140 and, thus,between the battery cells 122 and the electrical devices 116. Forexample, the solid-state relay assembly 114A may implement a first(e.g., charging only) connected state by switching and/or maintainingthe device-side switching device 144 in an activated (e.g., connected orclosed) state while switching and/or maintaining the battery-sideswitching device 142 in a deactivated (e.g., disconnected or open)state. Additionally, the solid-state relay assembly 114A may implement asecond (e.g., discharging only) connected state by switching and/ormaintaining the battery-side switching device 142 in the activated statewhile switching and/or maintaining the device-side switching device 144in the deactivated state. Furthermore, the solid-state relay assembly114A may implement a third (e.g., bi-directional) connected state byswitching and/or maintaining both the battery-side switching device 142and the device-side switching device 144 in the activated state.

On the other hand, the solid-state relay assembly 114A may implement adisconnected state by switching and/or maintaining both the battery-sideswitching device 142 and the device-side switching device 144 in thedeactivated state. As such, in the disconnected state, the solid-staterelay assembly 114A may block electrical power from flowing between thebattery-side terminal 138 and the device-side terminal 140 and, thus,block electrical power from flowing between the battery cells 122 andthe electrical devices 16. However, electrically conductive materialgenerally has some amount of inductance, which resists changes inelectrical current flowing therethrough.

In other words, the inductance present in a battery system 110 (e.g., anelectrical device 116 and/or a device-side electrical bus 126) mayresult in electrical current continuing to flow for some duration afterthe solid-state relay assembly 114A is switched from a connected stateto the disconnected state. In fact, in some instances, the inductancemay pull the device-side electrical bus 126 to a negative voltagerelative to the system ground 156 in an effort to continue the currentflow. Even with the device-side switching device 144 coupledtherebetween in the deactivated state, in such instances, thedevice-side electrical bus 126 may nevertheless pull the voltage at thefirst (e.g., common source) node 150 negative relative to a systemground 156 due to the first node 150 remaining electrically connected tothe device-side electrical bus 126, for example, via the intrinsic bodydiode 148 of the device-side switching device 144.

Unfortunately, at least in some instances, likelihood of a negativevoltage at the first (e.g., common source) node 150 affecting (e.g.,damaging) other components in a battery system 10, 110 may increase asmagnitude of the negative voltage increases. For example, as magnitudeof the negative voltage at the first node 50 increases, the voltage dropacross a battery-side switching device 142 coupled between the batterycells 122 and the first node 150 may increase. In fact, at least in someinstances, the negative voltage at the first node 150 may result in avoltage drop across the battery-side switching device 142 that causesits intrinsic body diode 148 to breakdown or avalanche, therebyaffecting (e.g., reduce) operational reliability of a solid-state relayassembly 114 and, thus, a battery system 10 in which the solid-staterelay assembly 114 is deployed.

Accordingly, to facilitate improving operational reliability, thepresent disclosure provides techniques for implementing and/or operatinga recirculation path 158 electrically coupled between a first (e.g.,common source) node 150 in a solid-state relay assembly 114 and a systemground 156. As in the example depicted in FIG. 4, in some embodiments,the recirculation path 158 may be implemented in the solid-state relayassembly 114A, for example, within a housing of the solid-state relayassembly 114A. Thus, in such embodiments, the solid-state relay assembly114A may include a ground terminal 160, which electrically couples therecirculation path 158 to the system ground 156. In other embodiments,the recirculation path 158 may be implemented external from thesolid-state relay assembly 114A, for example, as a separate (e.g.,distinct or discrete) device or component coupled to the solid-staterelay assembly 114A.

In any case, as in the depicted example, the recirculation path 158 mayinclude a first recirculation switching device 162 and a secondrecirculation switching device 164. As described above, the solid-staterelay assembly 114A may be implemented using semiconductor switchingdevices 134. For example, the first recirculation switching device 162may include a metal-oxide-semiconductor field-effect transistor 146implemented such that its source is coupled to the first (e.g., commonsource) node 150. Additionally, the second recirculation switchingdevice 164 may include a metal-oxide-semiconductor field-effecttransistor 146 implemented such that its source is coupled to the systemground 156, for example, via the ground terminal 160. In other words, asin the depicted example, the first recirculation switching device 162and the second recirculation switching device 164 may be electricallycoupled at a second (e.g., common drain) node 166. While a firstrecirculation switching device and a second recirculation switchingdevice are shown, it should be understood each recirculation switchingdevices may in turn comprise multiple recirculation switching devices.In other words, the first recirculation switching device 162 maycomprise a first, second, and third first recirculation switchingdevice. In turn, the second recirculation switching device 164 maycomprise multiple second recirculation switching devices—for example, afirst, second, and third second recirculation switching device.

To facilitate controlling operation of the recirculation path 158,control signals (e.g., output from the control system 118) may besupplied to the first recirculation switching device 162 and the secondrecirculation switching device 164. For example, a first (e.g., reversevoltage protection) recirculation control signal 168 may be supplied toa control input (e.g., gate) of the first recirculation switching device162 to selectively activate the first recirculation switching device162. Additionally, a second (e.g., inadvertent short-circuit protection)recirculation control signal 170 may be supplied to a control input(e.g., gate) of the second recirculation switching device 164 toselectively activate the second recirculation switching device 164.

In some embodiments, the first recirculation switching device 162 may beimplemented to protect one or more upstream components including thesecond recirculation switching device 164 from reverse voltage on adevice-side electrical bus 126, for example, by blocking electricalcurrent produced by the reverse voltage from flowing through theintrinsic body diode 148 of the second recirculation switching device164. Thus, in such embodiments, the first recirculation switching device162 may generally be in the deactivated (e.g., open) state when thesolid-state relay assembly 114A is in a connected state, but switch toand/or maintain the activated (e.g., closed) state immediately beforethe solid-state relay assembly 114A switches from the connected state tothe disconnected state. Additionally, in some embodiments, the secondrecirculation switching device 164 may be implemented to protect againstthe recirculation path 158 inadvertently producing a short-circuit tothe system ground 156. Thus, in such embodiments, the secondrecirculation switching device 164 may generally be in the deactivatedstate when the solid-state relay assembly 114A is in a connected stateand switch to and/or maintain the activated state immediately after thesolid-state relay assembly 114A switches from the connected state to thedisconnected state.

When the first recirculation switching device 162 and the secondrecirculation switching device 164 are both in the activated state, therecirculation path 158 may electrically connect the first (e.g., commonsource node) 150 of the solid-state relay assembly 114A to the systemground 156. In other words, the electrical current that the inductanceof the device-side electrical bus 126 and/or the electrical devices 116causes to continue to flow even after the solid-state relay assembly114A is switched to the disconnected state may recirculate from thesystem ground 156 to the first node 150 via the recirculation path 158and back to the electrical devices 116 via the intrinsic body diode 148of a device-side switching device 144. In this manner, the recirculationpath 158 may reduce magnitude of the voltage drop across a battery-sideswitching device 142, for example, by holding voltage at the first 150approximately (e.g., substantially) at the system ground 156. Asdescribed above, at least in some instance, this may facilitateimproving operational reliability of a solid-state relay assembly 114and, thus, a battery system 110, 10 in which the solid-state relayassembly 114 is implemented, for example, by reducing likelihood ofvoltage drop across a battery-side switching device 142 causing itsintrinsic body diode 148 to breakdown or avalanche.

An example of a process 172 for operating a battery system 110 includinga solid-state relay assembly 114 is described in FIG. 5. Generally, theprocess 172 includes operating a solid-state relay assembly in aconnected state (process block 174) and determining whether it isdesired to switch the solid-state relay assembly from the connectedstate to a disconnected state (decision block 176). Additionally, whenit is desired to switch to the disconnected state, the process 172includes activating a first recirculation switching device (processblock 178), switching the solid-state relay assembly from the connectedstate to the disconnected state (process block 180), activating a secondrecirculation switching device (process block 182), determining whetherrecirculation energy has been dissipated (decision block 184), anddeactivating the first recirculation switching device and the secondrecirculation switching device after the recirculation energy has beendissipated (process block 186).

In some embodiments, the process 172 may be implemented at least in partbased on circuit connections implemented (e.g., programmed) in a controlsystem 118. Additionally or alternatively, the process 172 may beimplemented at least in part by executing instructions stored in atangible, non-transitory, computer-readable medium, such as memory inthe control system 118, using processing circuitry, such as one or moreprocessors in the control system 118.

An example of a process 188 for implementing a solid-state relayassembly 114 with a recirculation path 158 is described in FIG. 6.Generally, the process 188 includes coupling a source of a battery-sideswitching device to a source of a device-side switching device (processblock 190), coupling a source of a first recirculation switching deviceto a common source node (process block 192), and coupling a drain of asecond recirculation switching device to a drain of the firstrecirculation switching device (process block 194). In some embodiments,the process 188 may be implemented at least in part by a manufacturer ofthe solid-state relay assembly 114 and/or a system integrator of abattery system 110 in which the solid-state relay assembly 114 isdeployed.

Another example of a solid-state relay assembly 114B is shown in FIG. 7.As depicted, the solid-state relay assembly 114B includes threebattery-side switching devices 142—namely a first battery-side switchingdevice 142A, a second battery-side switching device 142B, and a thirdbattery-side switching device 142C. While three battery-side switchingdevices are shown, this number should be understood as non-limiting. Invarious embodiments, the number of battery-side switching devices couldbe one, two, four, five, six, etc. Additionally, as depicted thesolid-state relay assembly 114B includes three device-side switchingdevices 144—namely a first device-side switching device 144A, a seconddevice-side switching device 144B, and a third device-side switchingdevice 144C. While three device-side switching devices are shown, thisnumber should be understood as non-limiting. In various embodiments, thenumber of device-side switching devices could be one, two, four, five,six, etc.

Furthermore, as depicted, the solid-state relay assembly 114B includesdriver circuitry 136. In particular, the solid-state relay assembly 114Bincludes battery-side driver circuitry 136A electrically coupled tocontrol inputs (e.g., gates) of the battery-side switching devices 142,device-side driver circuitry 136B electrically coupled to control inputsof the device-side switching devices 144, first recirculation drivercircuitry 136C electrically coupled to a control input of the firstrecirculation switching device 162, and second recirculation drivercircuitry 136D electrically coupled to a control input of the secondrecirculation switching device 164. It should be understood device-sidedriver circuitry 136B may, in various embodiments, have mirror circuitry(in other words, the same components) as battery-side driver circuitry136A.

In some embodiments, at least a portion of the driver circuitry 136 maybe electrically isolated, for example, to reduce the likelihood ofrecirculating electrical current flowing through the driver circuitry136 instead of the recirculation path 158. To facilitate providingelectrical isolation, as in the depicted example, one or moreoptocouplers 196 may be implemented in the driver circuitry 36.Additionally, as in the depicted example, an input-side of anoptocoupler 196 may receive an input signal generated based at least inpart on an input control signal (e.g., received from a control system118) relative to a power supply voltage 198 and the system ground 156.Furthermore, as in the depicted example, the output-side of theoptocoupler 196 may output an isolated signal generated based at leastin part on the input signal relative to an isolated power supply voltage100 and an isolated ground 102.

In some embodiments, the isolated ground 102 may be coupled to the first(e.g., common source) node 150 of a solid-state relay assembly 114. Inother words, at least in some instances, the isolated ground 102 maydiffer from system ground 156, for example, when the first recirculationswitching device 162 and the second recirculation switching device 164are both in the deactivated state and the solid-state relay assembly 114is in a connected state. Additionally, in some embodiments, the isolatedpower supply voltage 100 may be generated by passing the power supplyvoltage 198 through one or more transformers.

The disclosed system and method may have various advantages. Forexample, the disclosed system and method may prevent damage toelectronic components in the battery system. As a non-limiting example,the disclosed system and method may route current in the event of areverse-cycle of power in the battery system. In various embodiments,the system and method may allow for protection of circuit componentswhen there is overflow current or when the battery is otherwise turnedoff. This also may allow for various advantages to system safety.

As utilized herein, the terms “approximately,” “about,” “substantially”,and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed and claimed without restricting the scope of these features tothe precise numerical ranges provided. Accordingly, these terms shouldbe interpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described and claimedare considered to be within the scope of the invention as recited in theappended claims.

It should be noted that references to relative positions (e.g., “top”and “bottom”) in this description are merely used to identify variouselements as are oriented in the Figures. It should be recognized thatthe orientation of particular components may vary greatly depending onthe application in which they are used.

For the purpose of this disclosure, the term “coupled” means the joiningof two members directly or indirectly to one another. Such joining maybe stationary in nature or moveable in nature. Such joining may beachieved with the two members or the two members and any additionalintermediate members being integrally formed as a single unitary bodywith one another or with the two members or the two members and anyadditional intermediate members being attached to one another. Suchjoining may be permanent in nature or may be removable or releasable innature.

It is also important to note that the construction and arrangement ofthe system, methods, and devices as shown in the various examples ofembodiments is illustrative only. Although only a few embodiments havebeen described in detail in this disclosure, those skilled in the artwho review this disclosure will readily appreciate that manymodifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter recited. For example,elements shown as integrally formed may be constructed of multiple partsor elements show as multiple parts may be integrally formed, theoperation of the interfaces may be reversed or otherwise varied, thelength or width of the structures and/or members or connector or otherelements of the system may be varied, the nature or number of adjustmentpositions provided between the elements may be varied (e.g. byvariations in the number of engagement slots or size of the engagementslots or type of engagement). The order or sequence of any process ormethod steps may be varied or re-sequenced according to alternativeembodiments. Other substitutions, modifications, changes and omissionsmay be made in the design, operating conditions and arrangement of thevarious examples of embodiments without departing from the spirit orscope of the present inventions.

While this invention has been described in conjunction with the examplesof embodiments outlined above, various alternatives, modifications,variations, improvements and/or substantial equivalents, whether knownor that are or may be presently foreseen, may become apparent to thosehaving at least ordinary skill in the art. Accordingly, the examples ofembodiments of the invention, as set forth above, are intended to beillustrative, not limiting. Various changes may be made withoutdeparting from the spirit or scope of the invention. Therefore, theinvention is intended to embrace all known or earlier developedalternatives, modifications, variations, improvements and/or substantialequivalents.

The technical effects and technical problems in the specification areexemplary and are not limiting. It should be noted that the embodimentsdescribed in the specification may have other technical effects and cansolve other technical problems.

1. A battery system comprising: a battery; a solid-state relay system;and a control system; wherein the solid-state relay system comprises afirst battery-side switching device, first device-side switching device,and a recirculation path.
 2. The battery system of claim 1, wherein thesolid-state relay system further comprises a second battery-sideswitching device and third battery-side switching device, a seconddevice-side switching device and third device-side switching device. 3.The battery system of claim 1, wherein the recirculation path comprisesa first recirculation switching device.
 4. The battery system of claim3, wherein the recirculation path further comprises a secondrecirculation switching device.
 5. The battery of claim 3, wherein thefirst recirculation switching device comprises ametal-oxide-semiconductor field-effect transistor.
 6. The battery systemof claim 4, wherein both the first recirculation switching device andthe second recirculation switching device each comprise ametal-oxide-semiconductor field-effect transistor.
 7. The battery systemof claim 4, wherein the first recirculation switching device connects toa first recirculation driver circuitry and the second recirculationdevice connects to a second recirculation driver circuitry.
 8. Thebattery of claim 2, wherein each of the first battery-side switchingdevice, second battery-side switching device, third battery-sideswitching device, first device-side switching device, second device-sideswitching device and third device-side switching device each comprise ametal-oxide semiconductor field-effect transistor.
 9. A solid-staterelay assembly for a battery system comprising: a device-side drivercircuitry having a device-side switching device; a battery-side drivercircuitry having a battery-side switching device; a first recirculationdriver circuitry; a first recirculation switching device; a secondrecirculation switching device; and a second recirculation drivercircuitry.
 10. The solid-state relay assembly of claim 9 wherein thefirst recirculation switching device, second recirculation switchingdevice, or both the first recirculation switching device and secondrecirculation switching device comprise a metal-oxide semiconductorfield-effect transistor.
 11. The solid-state relay assembly of claim 9wherein the device-side switching device comprises a first, second, andthird device-side switching device.
 12. The solid-state relay assemblyof claim 11 wherein the battery-side switching device comprises a first,second, and third battery-side switching device.
 13. The solid-staterelay assembly of claim 9, wherein the device-side switching device is ametal-oxide semiconductor field-effect transistor.
 14. The solid-staterelay assembly of claim 9, wherein the battery-side switching device isa metal-oxide semiconductor field-effect transistor.